Navigation systems, such as an inertial navigation system (INS), can be found on a wide variety of mobile objects, such as, for example, commercial aircraft, military aircraft, weapons systems, and vehicles such as automobiles, railcars including locomotives, and marine vessels. Such navigation systems typically include a number of components, such as an inertial measurement unit (IMU) and a global positioning system (GPS), which generate navigation data and communicate with a navigation processor.
Many navigation systems also include a filter, such as a Kalman filter, which can compare the output of one navigation component, such as an IMU, with that of other navigation components, such as a GPS, to ensure that the components are functioning properly and to improve the overall accuracy of the navigation system. Such a filter often includes embedded models of the navigation components within the system. These models provide the filter with an indication of the characteristics and accuracy of the navigation components.
The component models embedded in a filter are often generalized, meaning that a single model is typically intended to represent the characteristics of an entire family of similar components. In many cases, such generalized models can dramatically limit the performance of the filter. Accordingly, a need exists for a way to adopt more specific models of navigation components within a filter.